Apparatus and method for connecting a compressor to a system

ABSTRACT

The compressor fittings, both suction and discharge, of a compressor can have braze rings positioned inside of the fittings as part of the compressor assembly. The braze ring can then be used by an installer to connect the compressor to corresponding suction and discharge lines of a system. The installer can insert the system tube or connection into the fitting and apply a torch until braze material can be seen exiting the joint around the system tube, which indicates the tube has been connected.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 61/756,702, filed Jan. 25, 2013, entitled APPARATUS AND METHOD FOR CONNECTING A COMPRESSOR TO A SYSTEM, which Application is incorporated by reference herein in its entirety.

BACKGROUND

The application generally relates to methods and apparatuses for connecting a compressor to a corresponding system such as a vapor compression system.

Aftermarket compressors (compressors installed into systems to replace a failed compressor) typically fail at a rate 3 to 4 times higher than original equipment manufacturer (OEM) initial installations. The high failure rate can be due to a variety of factors that can be present or occur in field installations. Some of the factors contributing to a high failure rate can include the presence of acids in the system from a motor burnout in the OEM compressor, the introduction of contaminants into the system during the installation process, the miswiring of the aftermarket compressor, overcharging the system with refrigerant during the installation process, or poor braze techniques when installing the aftermarket compressor.

Poor braze techniques can lead to the failure of the aftermarket compressor in a number of different ways. One way a poor braze technique can lead to a compressor failure is that the braze technique does not result in a hermetic seal with the compressor and refrigerant leaks from the system which can result in compressor damage. Another way a poor braze technique can lead to compressor failure is that contaminants and/or debris can be introduced into the system during the brazing process and cause resultant damage to the compressor.

Thus, what is needed is an apparatus and method for connecting a compressor to a corresponding system that makes tube brazing to the compressor easier, particularly for installers with poor braze techniques, while reducing the possibility of damage occurring to the compressor.

SUMMARY

The present invention is directed to a compressor including a shell having an enclosed space, a compression mechanism positioned within the enclosed space of the shell, and a motor positioned within the enclosed space of the shell and connected to the compression mechanism by a shaft to power the compression mechanism. The compressor also includes at least one compressor fitting fastened in the shell to permit passage of refrigerant between inside and outside of the shell. The the at least one compressor fitting includes a braze ring positioned within the at least one compressor fitting. The braze ring includes brazing material to connect a tube to the at least one compressor fitting.

The present invention is also directed to a method of connecting a compressor to a system. The method includes inserting a tube connected to a system into a fitting for a compressor having a braze ring position inside the fitting and heating a braze area of the fitting to melt a braze material of the braze ring. The method also includes inspecting an end of the fitting for braze material and stopping heating of the braze area upon braze material being identified around a circumference of the end of the fitting during the inspecting of the end.

In the present application, the compressor fittings, both suction and discharge, have braze rings embedded in the corresponding fitting as part of the compressor assembly from the manufacturer. The installer of the compressor simply needs to insert the system tube or connection into the fitting and apply a torch until material, which can be a silver color, is seen exiting the joint around the system tube.

One advantage of the present application is that it is much easier and more secure than typical brazing of the tube to the compressor using “stick” braze material.

Other features and advantages of the present application will be apparent from the following more detailed description of the embodiments, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment of a compressor.

FIG. 2 schematically shows an embodiment of a vapor compression system.

FIG. 3 schematically shows another embodiment of a vapor compression system.

FIG. 4 shows an embodiment of a braze ring for a suction fitting for a compressor.

FIG. 5 shows an embodiment of a braze ring for a discharge fitting for a compressor.

FIGS. 6 and 7 show different embodiments for holding a braze ring in a compressor fitting.

FIG. 8 shows a partial cross-sectional view of an embodiment of a suction fitting positioned in a compressor.

FIG. 9 shows an embodiment of a connection between a compressor fitting and a system connection.

Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 shows an embodiment of a reciprocating compressor. However, in other embodiments, the compressor can be any suitable type of hermetic or semi-hermetic compressor including, but not limited to, a rotary compressor, screw compressor, swag link compressor, scroll compressor, spool compressor, centrifugal compressor, or turbine compressor.

In FIG. 1, compressor 2 can have a suction port or fitting 14 that can be in fluid communication with an evaporator of a vapor compression system upon the connection of a suction line or conduit from the evaporator to the suction port 14. The suction port 14 can be in fluid communication with a suction plenum 12 through one or more openings in a motor cap 13. Refrigerant gas from the evaporator can enter the compressor 2 through the suction port 14 and then flows to the suction plenum 12 before being compressed. In one embodiment, the refrigerant gas from the suction port 14 can also fill the interior space of the compressor housing before flowing to the suction plenum 12.

The compressor 2 can use an electrical motor 18. As shown in FIG. 1, motor 18 is an induction motor having a stator 20 and a rotor 22. However, in other embodiments, any other suitable type of electrical motor may be used including, but not limited to, a switched reluctance (SR) motor or an electronically commutated permanent magnet motor (ECM). A shaft assembly 24 extends through the rotor 22. The bottom end 26 of the shaft assembly 24 extends into an oil sump 405 and includes a series of apertures 27. Connected to the shaft assembly 24 below the motor is a compression device 30, such as a piston assembly as shown in FIG. 1. In FIG. 1, the piston assembly 30 has two pistons. A connecting rod 32 is connected to a piston head 34, which moves back and forth within a cylinder 36. The cylinder 36 includes a gas inlet port 38 and a gas discharge port 40. Associated with these ports 38, 40 are associated suction valves and discharge valves. The gas inlet port 38 is connected to an intake tube 54, which is in fluid communication with the suction plenum 12.

The motor 18 can be activated by a signal in response to the satisfaction of a predetermined condition, for example, an electrical signal from a thermostat when a preset temperature threshold is reached. While a thermostat is used as an example, it should be known that any type of device or signal may be used to activate the compressor 2. When the compressor 2 is activated, electricity is supplied to the stator 20, and the windings in the stator 20 cause the rotor 22 to rotate. Rotation of the rotor 22 causes the shaft assembly 24 to turn. When the shaft assembly 24 is turning, oil sump fluid in the oil sump 405 enters the apertures 27 in the bottom end 26 of the shaft and then moves upward through and along the shaft 24 to lubricate the moving parts of the compressor 2.

Rotation of the rotor 22 also causes reciprocating motion of the piston assembly 30. As the assembly 30 moves to an intake position, the piston head 34 moves away from gas inlet port 38, the suction valve opens and refrigerant fluid is introduced into an expanding cylinder 36 volume. The gas is pulled from the suction plenum 12 through the intake tube 54 to the gas inlet port 38 where the gas passes through the suction valve and is introduced into the cylinder 36. When the piston assembly 30 reaches a first end (or top) of its stroke, shown by movement of the piston head 34 to the right side of the cylinder 36 of FIG. 1, the suction valve closes. The piston head 34 then compresses the refrigerant gas by reducing the cylinder 36 volume. When the piston assembly 30 moves to a second end (or bottom) of its stroke, shown by movement of piston head 34 to the left side of cylinder 36 of FIG. 1, a discharge valve is opened and the compressed refrigerant gas is expelled through the gas discharge port 40. The compressed refrigerant gas flows from the gas discharge port 40 into a muffler 50 then through an exhaust or discharge tube 52 to a discharge port or fitting. The discharge port can be in fluid communication with a condenser upon the connection of a discharge line or conduit from the condenser to the discharge port.

In one embodiment, the suction port or fitting 14 and the discharge port of fitting can be installed in a shell 98 of the compressor 2. The suction port 14 and the discharge port can each be inserted through a corresponding opening in the shell 98 of the compressor 2 and then fastened to the shell 98. In one embodiment, the suction port 14 and the discharge port can be fastened to the shell 98 by brazing or welding techniques to maintain a hermetic environment within the compressor shell 98. However, any suitable technique, e.g., epoxy, adhesives, compression fit, etc., to fasten the suction port 14 and the discharge port to the shell 98 can be used so long as the hermetic environment within the compressor is maintained.

The compressor 2 may be connected to a vapor compression system that is included in a heating, ventilation and air conditioning (HVAC) system, refrigeration system, chilled liquid system or other suitable type of system. FIGS. 2 and 3 show different embodiments of vapor compression systems. In FIG. 2, vapor compression system 300 includes the compressor 2, a condenser 304, and an evaporator 306, while in FIG. 3, vapor compression system 300 includes the compressor 2, a reversing valve 350, an indoor unit 354 and an outdoor unit 352.

The vapor compression system 300 can be operated as an air conditioning system, where the evaporator 306 is located inside a structure or indoors, i.e., the evaporator is part of indoor unit 354, to provide cooling to the air in the structure and the condenser 304 is located outside a structure or outdoors, i.e., the condenser is part of outdoor unit 352, to discharge heat to the outdoor air. The vapor compression system 300 can also be operated as a heat pump system, i.e., a system that can provide both heating and cooling to the air in the structure, with the inclusion of the reversing valve 350 to control and direct the flow of refrigerant from the compressor 2. When the heat pump system is operated in an air conditioning mode, the reversing valve 350 is controlled to provide for refrigerant flow as described above for an air conditioning system. However, when the heat pump system is operated in a heating mode, the reversing valve 350 is controlled to provide for the flow of refrigerant in the opposite direction from the air conditioning mode. When operating in the heating mode, the condenser 304 is located inside a structure or indoors, i.e., the condenser is part of indoor unit 354, to provide heating to the air in the structure and the evaporator 306 is located outside a structure or outdoors, i.e., the evaporator is part of outdoor unit 352, to absorb heat from the outdoor air.

In vapor compression system 300, whether operated as a heat pump or as an air conditioner, the compressor 2 is driven by the motor 18 that is powered by a motor drive 104. The motor drive 104 receives AC power having a particular fixed line voltage and fixed line frequency from AC power source 102 and provides power to the motor 18. In another embodiment, the motor 18 can be powered directly from the AC power source 102. The motor 18 used in the system 300 can be any suitable type of motor that can be powered by a motor drive 104.

Referring back to FIGS. 2 and 3, the compressor 2 compresses a refrigerant vapor and delivers the vapor to the condenser 304 through a discharge line (and the reversing valve 350 if configured as a heat pump). Some examples of refrigerants that may be used in vapor compression system 300 are: hydrofluorocarbon (HFC) based refrigerants, for example, R-410A, R-407C, R-404A, R-134a and R-32 (a component of R410A and R407C); hydrofluoro olefin (HFO) refrigerants, also known as “unsaturated HFCs,” such as R1234yf; inorganic refrigerants like ammonia (NH3), R-717 and carbon dioxide (CO2), R-744; hydrocarbon (HC) based refrigerants such as propane (R-290), isobutane (R-600a) or propene (R-1270), or any other suitable type of refrigerant. The refrigerant vapor delivered by the compressor 2 to the condenser 304 enters into a heat exchange relationship with a process fluid, e.g., air or water, and undergoes a phase change to a refrigerant liquid as a result of the heat exchange relationship with the process fluid. The condensed liquid refrigerant from the condenser 304 flows through an expansion device to the evaporator 306.

The condensed liquid refrigerant delivered to the evaporator 306 enters into a heat exchange relationship with another process fluid, e.g., air or water, and undergoes a phase change to a refrigerant vapor as a result of the heat exchange relationship with the process fluid. The vapor refrigerant in the evaporator 306 exits the evaporator 306 and returns to the compressor 2 by a suction line (and the reversing valve arrangement 350 if configured as a heat pump) to complete the cycle. In other embodiments, any suitable configuration of the condenser 304 and the evaporator 306 can be used in the system 300, provided that the appropriate phase change of the refrigerant in the condenser 304 and evaporator 306 is obtained. For example, if air is used as the process fluid to exchange heat with the refrigerant in the condenser 304 or the evaporator 306, then one or more fans can be used to provide the necessary airflow through the condenser 304 or evaporator 306. The motors for the one or more fans may be powered directly from the AC power source 102 or a motor drive, such as motor drive 104.

FIGS. 4-8 show embodiments of a braze ring in compressor suction fittings and compressor discharge fittings. A braze ring 60 can be positioned into one or both of the suction fitting or port 14 (see FIG. 4) or discharge fitting or port 16 (see FIG. 5), i.e., the compressor fittings, of the compressor 2 by the manufacturer. The braze ring 60 positioned in the compressor fitting(s) can be selected to have an appropriate size to provide sufficient brazing material or brazing alloy for the corresponding diameters of the fitting and connection and the area to be brazed. The braze ring 60 can be held in position on an inner surface 17 of the compressor fitting by any suitable technique that can maintain the braze ring in the desired position or location until the compressor 2 is installed into a corresponding system.

In FIGS. 4 and 5, a compression (or frictional) fit of the braze ring 60 is used to hold the braze ring 60 in the fitting 14, 16. As shown in FIG. 6, the braze ring 60 can reside or be embedded in a circumferential groove 62 in the internal surface 17 of the fitting 14 to hold the braze ring 60 in position. As shown in FIG. 7, the blaze ring 60 can be held in position by one or more protrusions, shoulders or flares 64 on the internal surface 17 of the discharge fitting 16 to hold the braze ring 60 in position. The protrusions, shoulders or flares 64 extend circumferentially around the inner surface 17 of the discharge fitting 16. However, in other embodiments, several individual protrusions 64 can be positioned at different locations around the inner surface 17 of the discharge fitting 16 to hold the braze ring 60 in position.

FIG. 8 shows an alternate embodiment of a suction fitting with a braze ring. The suction fitting 80 can have a first portion 82 that is substantially cylindrical and a second portion 84 that expands in diameter from the first portion 82. The second portion 84 can be attached in the compressor housing to form the hermetic seal for the compressor 2. The second portion 84 can have louvers 86 to direct refrigerant flow once it enters compressor 2 and a suction filter 88 to remove debris from the refrigerant flow entering the compressor 2.

In one embodiment, the braze ring 60 can be placed a predetermined distance from the end of the corresponding fitting. The predetermined distance for the placement of the braze ring 60 can be in the range of 0.25 inches to 1.5 inches in one embodiment. In other embodiments, the braze ring 60 can be placed at the same predetermined distance or different predetermined distances from the ends of the suction fittings 14 and the discharge fittings 16.

In another embodiment, more than one braze ring 60 can be placed in a suction fitting 14 or discharge fitting 16 if additional brazing material is required for the connection to the system. The braze rings 60 can be placed or positioned next to each other or spaced apart by a predetermined distance.

In still another embodiment, the braze ring can be a SilFos® ring with a brazing alloy having 15% silver (Ag).

The compressor 2 can be connected to a system using the following process. First, a compressor fitting 90 and a system connection or tube 92 can each be cleaned to remove any dirt and prepare the corresponding surfaces for brazing. Next, the system connection 92 can be inserted into the compressor fitting 90 until the system connection 92 contacts the braze ring (or a protrusion or shoulder if used to hold the braze ring). The corresponding braze area 94, i.e., the area of overlap between the compressor fitting 90 and the system connection 92, can be uniformly heated starting at the braze ring and extending over the brazing area 94. Finally, the brazing process is completed when braze material 96 can be seen around the entire circumference of the system connection 92 at the end of the compressor fitting 90, i.e., the joint between the system connection 92 and the compressor fitting 90. FIG. 9 shows an embodiment of a connection between a compressor fitting 90 and a system connection 92.

As would be appreciated by those of ordinary skill in the pertinent art, the functions of several elements of the present application may, in alternative embodiments, be carried out by fewer elements, or a single element. Similarly, in some embodiments, any functional element may perform fewer, or different, operations than those described with respect to the exemplary embodiment. Also, functional elements shown as distinct in the drawings may be incorporated within other functional elements, separated in different hardware or distributed in various ways in a particular implementation. Further, relative size and location are merely somewhat schematic and it is understood that not only the same but many other embodiments could have varying depictions.

All relative descriptions herein such as above, below, left, right, up, and down are with reference to the Figures, and not meant in a limiting sense. Relative descriptions such as inner and inward are with reference to being a direction toward the interior of a compressor shell whereas outer and outward are a direction away from the compressor. The shown assemblies can be understood as providing exemplary features of varying detail of certain embodiments, and therefore, components, modules, elements, and/or aspects of the drawings can be otherwise added to, combined, interconnected, sequenced, separated, interchanged, positioned, and/or rearranged without materially departing from the disclosed systems or methods. Additionally, the shapes and sizes of components are also exemplary and unless otherwise specified, can be altered without materially affecting or limiting the disclosed technology.

It is important to note that the construction and arrangement of the present application as shown in the various exemplary embodiments is demonstrative only. Although only a few embodiments have been described in detail in this application, those who review this application can readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters (e.g., temperatures, pressures, etc.), mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described in the application. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present application. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. In the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present application. Accordingly, the present application is not limited to a particular embodiment, but extends to various modifications that nevertheless fall within the scope of the appended claims.

Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described (i.e., those unrelated to the presently contemplated best mode of carrying out the invention, or those unrelated to enabling the invention). It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation. 

What is claimed is:
 1. A compressor comprising: a shell having an enclosed space; a compression mechanism positioned within the enclosed space of the shell; a motor positioned within the enclosed space of the shell and connected to the compression mechanism by a shaft to power the compression mechanism; at least one compressor fitting fastened in the shell to permit passage of refrigerant between inside and outside of the shell; and the at least one compressor fitting comprising a braze ring positioned within the at least one compressor fitting, the braze ring comprising brazing material to connect a tube to the at least one compressor fitting.
 2. A method of connecting a compressor to a system, the method comprising: inserting a tube connected to a system into a fitting for a compressor having a braze ring position inside the fitting; heating a braze area of the fitting to melt a braze material of the braze ring; inspecting an end of the fitting for braze material; and stopping heating of the braze area upon braze material being identified around a circumference of the end of the fitting during said inspecting an end. 